diff --git a/lua/dap.lua b/lua/dap.lua
index 53f180fa..b05f51ca 100644
--- a/lua/dap.lua
+++ b/lua/dap.lua
@@ -461,7 +461,7 @@ local function select_config_and_run(opts)
   lazy.async.run(function()
     local all_configs = {}
     local co = coroutine.running()
-    for _, config_provider in pairs(M.providers.configs) do
+    for provider, config_provider in pairs(M.providers.configs) do
       local configs = config_provider(bufnr)
       if type(configs) == "thread" then
         assert(
@@ -472,15 +472,21 @@ local function select_config_and_run(opts)
           coroutine.resume(configs, co)
         end)
         configs = coroutine.yield()
-      else
+      end
+      if islist(configs) then
         vim.list_extend(all_configs, configs)
+      else
+        local msg = "Configuration provider %s must return a list of configuration. Got: %s"
+        notify(msg:format(provider, vim.inspect(configs)), vim.log.levels.WARN)
       end
     end
+
     if #all_configs == 0 then
       local msg = 'No configuration found for `%s`. You need to add configs to `dap.configurations.%s` (See `:h dap-configuration`)'
       notify(string.format(msg, filetype, filetype), vim.log.levels.INFO)
       return
     end
+
     opts = opts or {}
     opts.filetype = opts.filetype or filetype
     lazy.ui.pick_if_many(